Electric furnace



Aug. 11, 1931. E MOORE 1,818,239

' ELECTRIC FURNACE Filed Sept. 25, 1929 2 Sheets-Sheet l l! william EMoore g- 11, 1931- w. E. MOORE 1,818,239

ELECTRI C FURNACE I Filed Sept. 25, 1929 2 Sheets-Sheet 2 William EMoore mmrtoz Patented Aug. 11, 1931 UNITED STATES} MOORE, OF PITTSBURGH,PENNSYLVANIA, ASSIGNOR TO PITTSRURGH- RESEARCH CORPORATION, OFPITTSBURGH, PENNSYLVANIA WILLIAM E.

PATENT ori ice ELECTRIC FURNACE Application filed September 25, 1929.Serial No. 895,058.

My present invention relates to improvements in electrlc furnaces andmore particularly to an improved furnace roof and operform a part ofthis speci cation and wherein like characters of reference denote likeor ating means therefor.

Heretofore it has been customary to charge electric furnaces through asidedoor after the furnace has been tapped, asby tilting. Thismethod'not only involves loss of time, heat and power, but causesconsiderable 1o difliculty in the charging of heavy scrap,

which must be broken into small pieces, and

the charging of light scrap, as the side door .bein near the metal line,does'not permit of the urnace being filled up to the roof with suchlight scrap. It has consequently been customer to charge such furnaceswith light scrap as 21111) as possible and then melt down the scrap, cutoff the power and recharge one or more times, involving consequent lossof time and power.

Several methods have been attempted for charging the furnace through thetop, such as the pull-back method, in which the entire roof is hinged atone side of the furnace on a horizontal axis in line with and below theelectrode guide columns. This method is objectionable in that ittiltsthe roof refractories through such an angle that both the refractoriesand the electrodes are 100 ened, strained and broken. It isalsodifficult, with the pull-back method, to make a tight top seal at theroof joint, as the tilting hinge is arranged low on the furnace shelland the roof has a sliding action when the pull-back motion is started.In some furnaces the roof has been arranged to lift off by means of acrane and be transported to one side of the furnace while the furnace ischarged through the top. This method, however, involves considerabledelay, and necessitates the application of separate guide columns thatdo not tilt with the furnace. v

An important object of my invention, therefore, is to provide a furnacewhich may 'be readily charged through its roof without the disadvantagesheretofore experienced in the art. 7 Other objects and advantages of myinvention will be a parent during the course of the followingescription. In the 'accom anyin drawings which corresponding partsthroughout the same,

Figure 1 is a front elevation of my improved furnace, s

Figure 2 is a. top plan view thereof, Figure 3 is an'elevation of theroof operatin mechanism, parts being broken away,

an h

Figure 4 is a top lan view thereof.

. In the drawings w erein for the purpose of illustration is shown apreferred embodiment of m I invention thenumeral 10 designates theurnace shell provided with the usual side doors 11 andhaving trunnionframes 12 at its sides which are provided with rockers 13 supported u onhorizontal supports 14. Tilting of the urnace is effected by means ofthe shaft 15. The furnace so far described is similar to that shown anddescribed in my prior Patents1,444,980 and, 1,532,599 and need not bedescribed in detail.

The roof arch ring 16, holding the movable refractory roof 17 isdetachably connected to the spectacle casting 18 by means of suitablebolts or other securing means 19. The spectacle casting 18 carries theelectrode guide columns 20 and may be quickly detached from the roofring 16 forrepairs. The roof ring 16 is further supported by'means ofguide rods 21 which are latchedinto suitable slot.

blocks 22 on the exterior face of the ring 16. A suitable cross bar orrod 23, having hooklike ends 24 which pivotally engage the upper ends ofthe rods 21, is carried by the upper ends of the ide columns 20.Electrode arms 25 are s idable vertically on the guide columns 20 andhave suitable clamps 26 which engage the electrodes 27. The constructionand operation of these electrode arms and clamps are clearly describedinmy priorpat-. ents referred to above. The electrodes are three innumber and arranged in a polyphase circuit, and suitable flexible cablesmay provided (not shown) of the tygs disclosed in my prior patentsreferred to. ater jackets 28 surround the electrodes and these ack- 1ets may be connected with flexible water supply pipes (not shown).

The roof arch ring 16 is connected to the furnace shell by means ofquick-acting T- head bolts 29 secured to the shell and operated byeccentric levers 30. The T-headed bolts engage suitable fork lugs on thearch ring 16. I

The spectacle casting 18 is provided with a horizontal extension 32 ofless thickness than the casting itself and provided with a verticallyarranged frusto-conical opening 33. It will be seen that the entire roofassembly, including the arch ring 16, the spectacle casting 18, guidecolumns 20 and electrodes 27 are independent of the furnace and aresecured thereto by the quick detachable bolts 29.

A vertically arranged hydraulic ram is arranged beneath the spectaclecasting 18 independently thereof and comprises a casing 34 mountedadjacent the support 14 and a plunger 35 which extends above the top ofthe casing 34 in line with the opening 33, the upper end of the plungerbeing frusto-conical in shape and adapted to be received in the opening33 when the plunger is raised. The furnace side of the plunger isprovided with a buttress stop 36 having a central projection 37 adaptedto fit between the arms of a downwardly projecting buttress fork 38 onthe casting 18 when the plunger is raised. The opposite side of theplunger is provided with an arm or projection 39 in which the end of onesection of a telescoping toggle shaft 39 is pivotally secured. A shaft40 extends up through the floor and through the casing support andterminates in an enlarged end which is pivotally received in theenlarged lower end of the toggle shaft 39. The lower end of the shaft 40is provided with a casting having two crank arms 41 to which arepivotally secured the connecting rods of two single action fluidpressure cylinders 42 of any suitable construction. The cylinders 42 andthe hydraulic ram may be controlled by any suitable valve tion shown indotted lines mechanism' (not shown).

The rockers 13 are geared to the supports 14 and the ram casing issecured to or formed integrally with one of the supports 14. The ram andtoggle connections are independent of the furnace and roof and theentire furnace and roof structure may be tilted with out interferencefrom the ram which is mounted on the floor.

In operation when it is desired to remove the roof for charging or forany reason, fluid pressure is admitted to the ram cylinder 43 and theplunger rises, its conical end entering the opening 33 and the buttressextension 36 moving up between the arms of the fork 38. Further upwardmovement of the plunger 35 raises the entire roof assembly into theposiin Figure 1, the

bolts 29 having been previously unfastened.

Pressure is then admitted to one of the cylinders 42 and motion istransmitted through the crank arm 41, shaft 40 and toggle shaft 39 tothe projection 39 on the plunger, to rotate the plunger and with it, theentire roof assembly, which assumes the position shown indotted lines inFigure 2. When the charging is completed the roof is swung back over thefurnace shell by means of the other cylinder 42 and when in the positionshown in dotted lines in Figure l is lowered onto the furnace shell bythe ram and the fasteners 29 are secured. The plunger is now completelydisengaged from the roof and spectacle casting and the furnace and roofmay be tilted in the usual way.

It will be seen that the roof partakes of two movements, one a shortvertical movement caused by the ram plunger and the other a swingingmovement caused by the cylinders 42 and toggle shaft 39. The verticalmovement breaks the seal between the roof and furnace shell and allowsthe roof and electrodes to clear the shell. The swinging movement givesaccess to the top of the furnace shell. The electrodes can be adjustedvertically at will. The cylinders and ram may be controlled by automaticvalves if desired but it is necessary that the roof be raised verticallybefore the swinging movement is started.

It is obvious that electric or other power may be used in place of thehydraulic power described.

While I have shown and described the pre; ferred embodiment of myinvention it is to be understood that various changes may be resorted towithout departing from the spirit of my invention or the scope of thesubjoined claims.

Having thus described my invention, what I claim and desire to protectby Letters Patent is:

1. An electric furnace comprising a tiltin shell. a roof detachablysecured thereto. and means arranged independently of said tilting shelland roof for swinging the roof away from the furnace shell.

2. An electric furnace comprising a tilting shell, a roof detachablysecured thereto, electrode supports carried by said roof, electrodescarried by said supports and extending through said roof. and meansarranged independently of said tilting shell and furnace roof forraising the roof and electrode assembly vertically from the shell andswinging the roof and electrode assembly away from said furnace shell.

3. An electric furnace comprising a shell, means to tilt said shell. aroof removably secured to said shell, a plunger arranged independentlyof said furnace shell and adapted to be raised to engage said furnaceroof, means to raise said plunger to raise the roof vertically from saidshell, and means to roand guides therefor carried by said roof, a

plunger arranged independently of said shell and roof, meansto raise theplunger to engage the roof and move the roof and the associatedelectrodes and guides vertically from 9 said shell, and means to rotatesaid plunger to'swing the roof and electrode mechanism away from saidshell.

5. An electric furnace com rising a shell, means to tilt said shell, aroo removably se- 5 cured thereto, electrodes and electrode guidescarried by said roof independently of the shell, aplunger casingarranged adjacent said shell and independently thereof, a plunger insaid casing, means to move the o plunger vertically to engage and raisethe roof and associated electrode mechanism vertically away-from saidshell, and means to rotate said plunger to swin the roof and electrodemechanism away rom the furnace 5 shell.

6. An electric furnace comfprising a shell, means to tilt said shell, aroo detachably secured to said-shell, a spectacle casting detachablysecured to said roof, electrode guides carried by said casting,electrodes mounted on said guides, a plunger casing arranged adjacentsaid shell and independently thereof, aplunger in said casing, means onsaid plunger to engage said spectacle casting when the plunger israised, means to raise said plunger to raise the s ectacle casting androof vertically away om said shell and means to rotate sai plunger toswing said casting'and roof away from said shell.

7. An electric furnace comprising a tilting shell, a roof detachablysecured to said shell, electrodes mounted on said roof, a hydraulic ramarranged adjacent said shell and independently thereof, and comprising acasing and a plunger, means to move said plunger vertically to en agesaid roof and move it vertically away rom said shell, a lateralprojection on said plunger, a shaft ournaled adjacent sa'id ram casing,and a telescoping toggle shaft connecting said shaft with the lateralprojection on the plunger, whereby rotation of theshaft operates throughthe toggle shaft to rotate the plunger and swing the furnace roof andelectrodes away from the furnace shell. 7

8. An electric furnace comprisin a shell, means to tilt the shell, aroof detac ably secured to said shell, aspectacle castin detachablysecured to said roof, electro e gulde mechanism carried by said casting,electrodes carried thereby, a hydraulic ram arranged adjacent saidfurnace shell and independently thereof, and comprising a casin an aplunger therein, means on said .p unger to removably engage thespectacle casting, whereby upward movement of the plunger raises thecasting and roof vertically away from said furnace shell, a lateralprojection on said plunger, a shaft, 9. telescopin toggle shaftconnecting the shaft and the ateral projection on the plunger, and meansto rotate the shaft when the plunger is in its raised position to rotatethe plun er through the toggle shaft for swinging t e casting and roofaway from the furnace shell.

9. An electric furnace comprising a shell, a roof removably securedthereto, means independent of said furnace for raisin the roofvertically from said furnace Shel? and pivotin it away from the furnaceshell, and means or tilting said shell with the roof in positionthereon.

I 10. An electric furnace comprising a tilting shell, a roof detachablysecured thereto and capable of being tilted'therewith, and meansarranged independently of said tilting shell and roof for swinging theroof away from the furnace shell.

11.. An electric furnace comprising a tilting shell, a roof detachablysecured thereto and capable of being tilted therewith, and meansarranged independently of said furnace for raising the roof verticallyfrom said 828% and pivoting it away from the furnace s e 12. An electricfurnace comprising a shell, a removable roof therefor, electrodesextending through said roof and supported thereon, electrode coolingackets carried by said roof in proximity to said electrodes, meansindependent of said furnace for raising the roof vertically from saidfurnace shell and swinging it away from the furnace shell, and means fortilting said shell with the roof and electrodes in position thereon. 13.An electric furnace comprising a tilting shell having substantiallydiametrically opposite doors arranged in the tilting plane 0 thefurnace, a removable roof for said shell, electrodes extending throughsaid roof and supported thereby, said roof and electrodes being capableof being tilted with said shell, and means arranged independently ofsaid furnace shelland roof for swinging the rhoofi and electrodes awayfrom the furnace s e In testimony whereof I aflix m signature.

' WILLIAM E. OORE.

